The present invention relates to a double slide, focal plane shutter for photographic cameras.
Various kinds of focal plane shutters are known and a specific variety includes for example plural lamellas instead of shutter curtains whereby two particular lamellas define the slit which is to be moved across the image aperture or window for exposure of the film behind the aperture. Each of these lamellas does not cover the image aperture in its entirety so that plural lamellas were arranged in two sets, each set including one lamella having one edge to define the slit together with an edge of a lamella of the other set. The lamellas of each set in the known arrangement are disposed in a superimposing relationship and are individually controlled in one fashion or another and with regard to their position and movement. As a consequence, these known lamella shutters are quite complicated.
The reason for employing such multiple lamella type slides for shutters was that each individual lamella is not as high as the image aperture so that a set of lamellas when retracted can be aligned and forms a stack. The so aligned lamellas as covering each other occupy in that fashion an area which is smaller than the area of the image aperture and the saving in space, particularly for the retracted set of lamellas, is the main reason for using this kind of a shutter. Nevertheless, the complications with regard to moving and guiding the lamellas are a disadvantageous trade-off.